Diagenesis and reservoir quality in tight gas sandstones: The fourth member of the Upper Triassic Xujiahe Formation, Central Sichuan Basin, Southwest China

摘要: Mineralogical, petrographic, and geochemical analyses were performed to investigate the sandstone composition texture, pore system, diagenetic minerals of Upper Triassic sandstones in Central Sichuan Basin, Southwest China. The results show that authigenic quartz, clay minerals, carbonates are main pore-filling constituents. systems consist intergranular porosity, secondary microporosity, microfractures. Loss depositional porosity is greater due compaction than cementation. Eodiagenesis includes mechanical compaction, precipitation early calcite cements, kaolinite, smectite, leaching feldspars by meteoric water. Mesodiagenesis consists framework grain dissolution, subsequent illite, late carbonate cements. Six lithofacies identified on basis petrographic analyses, namely, (a) argillaceous sandstones; (b) poorly sorted (c) quartz-cemented (d) carbonate-cemented (e) clay-mineral-cemented sandstones, (f) clean with abundant porosity. best reservoir-quality rocks have high percentages detrital quartz but low matrix, cement. Differences textural compositional attributes various significantly affect porosity-depth trends. evolution pathways prediction models reconstructed integrated data. This work provides insights into describing different analysis helps how texture influence diagenesis reservoir quality tight gas sandstones.